* President tells Republicans to come together
* Vote to open repeal debate next week
* Bipartisan fixes for Obamacare pushed by Democrats (Adds reaction from senators)
WASHINGTON, July 19 (Reuters) - U.S. President Donald Trump scolded Senate Republicans on Wednesday for failing to reach agreement on repealing or overhauling Obamacare, demanding they not leave Washington for a planned August recess until they can find common ground on healthcare.
Trump's call to action on Obamacare, at a White House lunch with 49 senators, was in sharp contrast to his hands-off approach to the Senate's work over the last few weeks.
On Tuesday, after the seven-year Republican quest to repeal and replace Democratic former President Barack Obama's signature healthcare law collapsed in the Senate, he suggested he would be fine with letting Obamacare fail.
But at the lunch he told the senators he wanted more than a straight repeal and also wanted to replace Obamacare. "We're close. We're very close," Trump said at the start of the meeting.
He demanded that lawmakers keep their campaign promises and find a new approach to healthcare.
"For seven years you promised the American people you would repeal Obamacare. People are hurting and, frankly, inaction is not an option," Trump told his fellow Republicans. "Any senator who votes against starting debate is really telling America that you're fine with Obamacare."
"We can repeal, but we should repeal and replace and we shouldnt leave town until this is complete," he said.
Senate Majority Leader Mitch McConnell said he will go ahead with a vote early next week to begin debate on a repeal of the Affordable Care Act, popularly known as Obamacare, despite indications it will fail after the defections on Tuesday of at least three Republican senators.
Moderate Republican Senators Susan Collins, Lisa Murkowski, and Shelley Moore Capito said they oppose McConnell's plan for a repeal that would take effect in two years, giving Congress time to develop a replacement. All three attended the lunch.
With Democrats united in opposition to repeal, McConnell can only lose two votes from his 52-48 majority in the 100-seat Senate to pass healthcare legislation.
After the lunch, McConnell said that if Republicans get the 50 votes needed to open debate on a healthcare bill, the Senate could amend it. "I think we all agree it's better to both repeal and replace, but we could have a vote on either," he said.
McConnell said administration officials, including Vice President Mike Pence, Health and Human Services Secretary Tom Price and others, would head to Capitol Hill on Wednesday night to work "with some of our members who at least so far have had some difficulty getting to yes."
'HONOR OUR PROMISE'
Repealing and replacing Obamacare was a top campaign promise for Trump and Republicans in Congress, who say it is a costly intrusion into the healthcare system.
But the reality has been difficult for a party divided between moderates concerned the Senate bill would eliminate insurance for millions of low-income Americans and conservatives who want to see even deeper cuts to Obamacare, which boosted the number of Americans with health insurance through mandates on individuals and employers, and income-based subsidies.
"We have to honor our promise," Republican Senator Ted Cruz told reporters. "For seven years Republicans have told the voters, if you elect us, well repeal Obamacare. I think we will look like fools if we cant deliver on that promise."
Republican Senator Bob Corker said the discussion has focused on winning over Republicans from states that have expanded the Medicaid program for low-income Americans under Obamacare. That includes Capito of West Virginia and Rob Portman of Ohio.
"For folks, especially in Medicaid expansion states, I think there have been some offers already this morning," Corker said without providing details. He described the lunch as upbeat.
Democrats, clearly delighted with the turn of events, have welcomed the Republicans' failure to replace Obamacare as an opportunity to work together. Republicans conceded their other options may be exhausted.
The No. 2 Senate Republican, John Cornyn, told reporters it was "unfortunate" that he expected bipartisan talks to begin.
"Democrats are strongly committed to Obamacare and are unwilling to admit structural problems, which create the problems we are having in the individual market today," Cornyn said. "But we'll do the best we can with the hand we've been dealt."
If senators try to shore up Obamacare, an initial hurdle in coming weeks will be boosting faltering state insurance markets by ensuring that insurers keep receiving subsidies that help lower the cost of insurance for low-income individuals.
The Trump administration will continue making the subsidy payments through August while a related Republican lawsuit is pending. The uncertainty beyond that has rattled insurers.
Republican senators have acknowledged the need to address the unstable markets but resisted Democratic calls to fund the subsidies without accompanying reforms, calling it a "bailout" for insurance companies.
Funding for the Children's Health Insurance Program, a part of the Medicaid government health insurance program for the poor and disabled, known as CHIP, expires on Sept. 30 and will require reauthorization.
Bills to address the subsidy payments and CHIP would likely require 60 votes for passage, acting as a barometer of how inclined Republicans and Democrats are to work together, industry lobbyists and experts said. (Writing by John Whitesides; Additional reporting by Susan Cornwell, Richard Cowan, Yasmeen Abutaleb and Susan Heavey; Editing by Mary Milliken and Jonathan Oatis)